ia32: Remove redundant CTX preservation from intrinsics; tweak definition of CTX.

runtime/vm/intrinsifier_ia32.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // The intrinsic code below is executed before a method has built its frame.
 // The return address is on the stack and the arguments below it.
 // Registers EDX (arguments descriptor) and ECX (function) must be preserved.
 // Each intrinsification method returns true if the corresponding
 // Dart method was intrinsified.
 
@@ skipping 792 matching lines @@
   __ SmiTag(EAX);
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_absAdd(Assembler* assembler) {
   // static void _absAdd(Uint32List digits, int used,
   //                     Uint32List a_digits, int a_used,
   //                     Uint32List r_digits)
 
-  // Preserve CTX to free ESI.
-  __ pushl(CTX);
-  ASSERT(CTX == ESI);
-
-  __ movl(EDI, Address(ESP, 6 * kWordSize));  // digits
-  __ movl(EAX, Address(ESP, 5 * kWordSize));  // used is Smi
+  __ movl(EDI, Address(ESP, 5 * kWordSize));  // digits
+  __ movl(EAX, Address(ESP, 4 * kWordSize));  // used is Smi
   __ SmiUntag(EAX);  // used > 0.
-  __ movl(ESI, Address(ESP, 4 * kWordSize));  // a_digits
-  __ movl(ECX, Address(ESP, 3 * kWordSize));  // a_used is Smi
+  __ movl(ESI, Address(ESP, 3 * kWordSize));  // a_digits
+  __ movl(ECX, Address(ESP, 2 * kWordSize));  // a_used is Smi
   __ SmiUntag(ECX);  // a_used > 0.
-  __ movl(EBX, Address(ESP, 2 * kWordSize));  // r_digits
+  __ movl(EBX, Address(ESP, 1 * kWordSize));  // r_digits
 
   // Precompute 'used - a_used' now so that carry flag is not lost later.
   __ subl(EAX, ECX);
   __ incl(EAX);  // To account for the extra test between loops.
   __ pushl(EAX);
 
   __ xorl(EDX, EDX);  // EDX = 0, carry flag = 0.
   Label add_loop;
   __ Bind(&add_loop);
   // Loop a_used times, ECX = a_used, ECX > 0.
@@ skipping 17 matching lines @@
   __ movl(FieldAddress(EBX, EDX, TIMES_4, TypedData::data_offset()), EAX);
   __ incl(EDX);  // Does not affect carry flag.
   __ decl(ECX);  // Does not affect carry flag.
   __ j(NOT_ZERO, &carry_loop, Assembler::kNearJump);
 
   __ Bind(&last_carry);
   __ movl(EAX, Immediate(0));
   __ adcl(EAX, Immediate(0));
   __ movl(FieldAddress(EBX, EDX, TIMES_4, TypedData::data_offset()), EAX);
 
-  // Restore CTX and return.
-  __ popl(CTX);
   // Returning Object::null() is not required, since this method is private.
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_absSub(Assembler* assembler) {
   // static void _absSub(Uint32List digits, int used,
   //                     Uint32List a_digits, int a_used,
   //                     Uint32List r_digits)
 
-  // Preserve CTX to free ESI.
-  __ pushl(CTX);
-  ASSERT(CTX == ESI);
-
-  __ movl(EDI, Address(ESP, 6 * kWordSize));  // digits
-  __ movl(EAX, Address(ESP, 5 * kWordSize));  // used is Smi
+  __ movl(EDI, Address(ESP, 5 * kWordSize));  // digits
+  __ movl(EAX, Address(ESP, 4 * kWordSize));  // used is Smi
   __ SmiUntag(EAX);  // used > 0.
-  __ movl(ESI, Address(ESP, 4 * kWordSize));  // a_digits
-  __ movl(ECX, Address(ESP, 3 * kWordSize));  // a_used is Smi
+  __ movl(ESI, Address(ESP, 3 * kWordSize));  // a_digits
+  __ movl(ECX, Address(ESP, 2 * kWordSize));  // a_used is Smi
   __ SmiUntag(ECX);  // a_used > 0.
-  __ movl(EBX, Address(ESP, 2 * kWordSize));  // r_digits
+  __ movl(EBX, Address(ESP, 1 * kWordSize));  // r_digits
 
   // Precompute 'used - a_used' now so that carry flag is not lost later.
   __ subl(EAX, ECX);
   __ incl(EAX);  // To account for the extra test between loops.
   __ pushl(EAX);
 
   __ xorl(EDX, EDX);  // EDX = 0, carry flag = 0.
   Label sub_loop;
   __ Bind(&sub_loop);
   // Loop a_used times, ECX = a_used, ECX > 0.
@@ skipping 13 matching lines @@
   __ Bind(&carry_loop);
   // Loop used - a_used times, ECX = used - a_used, ECX > 0.
   __ movl(EAX, FieldAddress(EDI, EDX, TIMES_4, TypedData::data_offset()));
   __ sbbl(EAX, Immediate(0));
   __ movl(FieldAddress(EBX, EDX, TIMES_4, TypedData::data_offset()), EAX);
   __ incl(EDX);  // Does not affect carry flag.
   __ decl(ECX);  // Does not affect carry flag.
   __ j(NOT_ZERO, &carry_loop, Assembler::kNearJump);
 
   __ Bind(&done);
-  // Restore CTX and return.
-  __ popl(CTX);
   // Returning Object::null() is not required, since this method is private.
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_mulAdd(Assembler* assembler) {
   // Pseudo code:
   // static int _mulAdd(Uint32List x_digits, int xi,
   //                    Uint32List m_digits, int i,
   //                    Uint32List a_digits, int j, int n) {
@@ skipping 26 matching lines @@
   __ movl(EAX, Address(ESP, 6 * kWordSize));  // xi is Smi
   __ movl(EBX, FieldAddress(ECX, EAX, TIMES_2, TypedData::data_offset()));
   __ testl(EBX, EBX);
   __ j(ZERO, &no_op, Assembler::kNearJump);
 
   // EDX = SmiUntag(n), no_op if n == 0
   __ movl(EDX, Address(ESP, 1 * kWordSize));
   __ SmiUntag(EDX);
   __ j(ZERO, &no_op, Assembler::kNearJump);
 
-  // Preserve CTX to free ESI.
-  __ pushl(CTX);
-  ASSERT(CTX == ESI);
-
   // EDI = mip = &m_digits[i >> 1]
-  __ movl(EDI, Address(ESP, 6 * kWordSize));  // m_digits
-  __ movl(EAX, Address(ESP, 5 * kWordSize));  // i is Smi
+  __ movl(EDI, Address(ESP, 5 * kWordSize));  // m_digits
+  __ movl(EAX, Address(ESP, 4 * kWordSize));  // i is Smi
   __ leal(EDI, FieldAddress(EDI, EAX, TIMES_2, TypedData::data_offset()));
 
   // ESI = ajp = &a_digits[j >> 1]
-  __ movl(ESI, Address(ESP, 4 * kWordSize));  // a_digits
-  __ movl(EAX, Address(ESP, 3 * kWordSize));  // j is Smi
+  __ movl(ESI, Address(ESP, 3 * kWordSize));  // a_digits
+  __ movl(EAX, Address(ESP, 2 * kWordSize));  // j is Smi
   __ leal(ESI, FieldAddress(ESI, EAX, TIMES_2, TypedData::data_offset()));
 
   // Save n
   __ pushl(EDX);
   Address n_addr = Address(ESP, 0 * kWordSize);
 
   // ECX = c = 0
   __ xorl(ECX, ECX);
 
   Label muladd_loop;
@@ skipping 38 matching lines @@
   __ j(NOT_CARRY, &done, Assembler::kNearJump);
 
   Label propagate_carry_loop;
   __ Bind(&propagate_carry_loop);
   __ addl(ESI, Immediate(Bigint::kBytesPerDigit));
   __ incl(Address(ESI, 0));  // c == 0 or 1
   __ j(CARRY, &propagate_carry_loop, Assembler::kNearJump);
 
   __ Bind(&done);
   __ Drop(1);  // n
-  // Restore CTX and return.
-  __ popl(CTX);
 
   __ Bind(&no_op);
   __ movl(EAX, Immediate(Smi::RawValue(1)));  // One digit processed.
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_sqrAdd(Assembler* assembler) {
   // Pseudo code:
   // static int _sqrAdd(Uint32List x_digits, int i,
@@ skipping 26 matching lines @@
   __ movl(EAX, Address(ESP, 3 * kWordSize));  // i is Smi
   __ leal(EDI, FieldAddress(EDI, EAX, TIMES_2, TypedData::data_offset()));
 
   // EBX = x = *xip++, return if x == 0
   Label x_zero;
   __ movl(EBX, Address(EDI, 0));
   __ cmpl(EBX, Immediate(0));
   __ j(EQUAL, &x_zero, Assembler::kNearJump);
   __ addl(EDI, Immediate(Bigint::kBytesPerDigit));
 
-  // Preserve CTX to free ESI.
-  __ pushl(CTX);
-  ASSERT(CTX == ESI);
-
   // ESI = ajp = &a_digits[i]
-  __ movl(ESI, Address(ESP, 3 * kWordSize));  // a_digits
+  __ movl(ESI, Address(ESP, 2 * kWordSize));  // a_digits
   __ leal(ESI, FieldAddress(ESI, EAX, TIMES_4, TypedData::data_offset()));
 
   // EDX:EAX = t = x*x + *ajp
   __ movl(EAX, EBX);
   __ mull(EBX);
   __ addl(EAX, Address(ESI, 0));
   __ adcl(EDX, Immediate(0));
 
   // *ajp++ = low32(t)
   __ movl(Address(ESI, 0), EAX);
   __ addl(ESI, Immediate(Bigint::kBytesPerDigit));
 
   // int n = used - i - 1
-  __ movl(EAX, Address(ESP, 2 * kWordSize));  // used is Smi
-  __ subl(EAX, Address(ESP, 4 * kWordSize));  // i is Smi
+  __ movl(EAX, Address(ESP, 1 * kWordSize));  // used is Smi
+  __ subl(EAX, Address(ESP, 3 * kWordSize));  // i is Smi
   __ SmiUntag(EAX);
   __ decl(EAX);
   __ pushl(EAX);  // Save n on stack.
 
   // uint64_t c = high32(t)
   __ pushl(Immediate(0));  // push high32(c) == 0
   __ pushl(EDX);  // push low32(c) == high32(t)
 
   Address n_addr = Address(ESP, 2 * kWordSize);
   Address ch_addr = Address(ESP, 1 * kWordSize);
@@ skipping 44 matching lines @@
   __ movl(EAX, cl_addr);  // t = c
   __ movl(EDX, ch_addr);
   __ addl(EAX, Address(ESI, 0));  // t += *ajp
   __ adcl(EDX, Immediate(0));
 
   // *ajp++ = low32(t)
   // *ajp = high32(t)
   __ movl(Address(ESI, 0), EAX);
   __ movl(Address(ESI, Bigint::kBytesPerDigit), EDX);
 
-  // Restore CTX and return.
   __ Drop(3);
-  __ popl(CTX);
   __ Bind(&x_zero);
   __ movl(EAX, Immediate(Smi::RawValue(1)));  // One digit processed.
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_estQuotientDigit(Assembler* assembler) {
   // Pseudo code:
   // static int _estQuotientDigit(Uint32List args, Uint32List digits, int i) {
   //   uint32_t yt = args[_YT];  // _YT == 1.
@@ skipping 849 matching lines @@
                         Isolate::current_tag_offset());
   // Set return value to Isolate::current_tag_.
   __ movl(EAX, current_tag_addr);
   __ ret();
 }
 
 #undef __
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32